Consequences of altered precipitation, warming, and clipping for plant productivity, biodiversity, and grazing resources at three northern temperate grassland sitesReport as inadecuate




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grassland, climate change, grazing

White, Shannon R

Supervisor and department: Bork, Edward W Agricultural, Food, and Nutritional Sciences Cahill, James F Jr Biological Sciences

Examining committee member and department: Mackenzie, M. Derek Renewable Resources Vinebrooke, Rolf Biological Sciences Henry, Greg Geography

Department: Department of Biological Sciences

Specialization: Ecology

Date accepted: 2013-01-29T15:27:58Z

Graduation date: 2013-06

Degree: Doctor of Philosophy

Degree level: Doctoral

Abstract: There is limited understanding about how altered precipitation and warming associated with climate change affect grassland systems. Also, although grasslands commonly support herbivores, it is unclear how grazing influences responses to climate change. To address these knowledge gaps, I carried out a fully controlled and factorial three-year, multi-site experiment simulating climate change and grazing via clipping. This experiment was conducted at three sites, chosen to broadly represent northern temperate grassland in the region, and each of Canada’s prairie provinces. I increased air temperature by 2-4°C, reduced precipitation by 60%, and clipped plants at low and high intensity. At one site, I also applied added +60% precipitation. I monitored an array of responses, including plant biomass and biodiversity, and grazing resources. Shoot biomass decreased strongly with reduced precipitation and clipping, and tended to decrease with warming. However, shifts in root: shoot ratio and associated root biomass responses enabled stability of total biomass. With respect to grazing resources, herbage availability and quality decreased with reduced precipitation and warming; decline in herbage availability was less pronounced with warming than reduced precipitation. To assess biodiversity responses, I evaluated indirect and direct treatment effects on species richness and evenness. Across sites, richness declined with environmental changes associated with all three treatments. However, evenness responses varied by site, and were overall more resistant. I also assessed changes in similarity between the seed bank and aboveground vegetation at one location. Precipitation and clipping affected similarity between the seed bank and vegetation, while warming did not. Across sites, responses were generally consistent, except for the driest site, which remained largely resistant to reduced precipitation. Generally, the grasslands were highly responsive to warming, altered precipitation, and clipping, with negative implications for ecosystem function and biodiversity. However, productivity and biodiversity responses were asynchronous; productivity was more responsive to precipitation and clipping, while richness was more sensitive to increased air temperature. As well, results suggest that management will not substantially influence responses to climate change. Overall, maintenance of total biomass suggests that ecosystem function is relatively resistant to climate change, but climate change has negative ramifications for biodiversity and grazing resources.

Language: English

DOI: doi:10.7939-R3KH56

Rights: Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.





Author: White, Shannon R

Source: https://era.library.ualberta.ca/


Teaser



Grass emerges like the tip of an iceberg in a land too dry for forest, too wet for desert, shows only its hair.
On the surface, foliage, flowers, blades and seeds while beneath, so much unseen, so much unknown. – Diane Buchanan “The Warp and Woof” in Writing the Land “The middle ground is a mess.
It is fascinating to study, and rich in wonderful biology.
But by studying it, do not expect universal rules, even simple contingent and general rules, to emerge.
If and when they do, treasure them.” – John H.
Lawton, 1999, Oikos 84(2) University of Alberta Consequences of altered precipitation, warming, and clipping for plant productivity, biodiversity, and grazing resources at three northern temperate grassland sites by Shannon Rita White A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Ecology Biological Sciences ©Shannon R.
White Spring 2013 Edmonton, Alberta Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only.
Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the authors prior written permission. Abstract There is limited understanding about how altered precipitation and warming associated with climate change affect grassland systems.
Also, although grasslands commonly support herbivores, it is unclear how grazing influences responses to climate change.
To address these knowledge gaps, I carried out a fully...





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